docs: def acquire_filename(self, name):
          """Acquire a file name and return its id and its signature.
          """
  
          id_ = self.__id_lut.get(name)
          # Is this a new entry?
          if id_ is None:
              # then create one...
              id_ = self.__next_id
              self.__next_id += 1
              self.__id_lut[name] = id_
              entry = filename_entry_t(name)
              self.__entries[id_] = entry
          else:
              # otherwise obtain the entry...
              entry = self.__entries[id_]
  
          entry.inc_ref_count()
          return id_, self._get_signature(entry)